PROJECT SUMMARY/ABSTRACT The goal of this proposal is to develop a longitudinal study of patterns of care and health outcomes among individuals who were diagnosed with disorders of sex development (DSD). We propose a study of DSD patients from three large integrated health care systems (HCS): Kaiser Permanente Southern California (KPSC), Kaiser Permanente Georgia (KPGA), and Kaiser Permanente Mid-Atlantic States (KPMAS). These HCS share similarly structured electronic medical records (EMRs) and represent a geographically, socio- economically, and demographically diverse population of nearly 5 million members. Most methods of data collection described in the current application have been successfully implemented in our recently completed or ongoing studies of transgender people. Applying these methods to the 2006-2015 data at the participating sites, we identified 19,233 patients with ?likely DSD? based on diagnoses or keywords in the medical records. In addition, 47,107 individuals were identified as having ?possible DSDs? (e.g., non-specified uterine anomalies or hypospadias). The proposed project will address three areas of importance in DSD research: 1) patterns and guideline-concordance of care; 2) controversies in treatment; and 3) comorbidities and long-term health outcomes. We will use validated EMR data to estimate the percentages of confirmed DSD patients who underwent diagnostic workup and received care according to current recommendations. We will examine whether guideline concordant DSD management is associated with health outcomes, such as the need for additional care and behavioral health problems later in life. The often cited area of disagreement is the optimal timing of sex assignment surgery in cases of atypical or ambiguous genitalia with some advocating early procedures and others arguing for a deferral. Another controversial issue is the common practice of a prophylactic gonadectomy for DSD patients whose karyotype includes Y-chromosome material (+Y DSD). We will use relevant KPSC, KPGA, and KPMA diagnostic and procedure codes to identify genital surgery and gonadectomies. Using these data we will assess the association between timing of gender assignment procedures and surgical complications, gender dysphoria, or other health problems later in life. We will also review pathology reports to estimate the frequency and determinants of ?positive gonadectomy,? i.e., with evidence of malignant or premalignant lesions. We will then compare measures of health status of DSD patients to the corresponding measures among age- and membership matched non-DSD male and non-DSD female HCS enrollees (reference cohort). We will examine the incidence and prevalence of comorbidities and long-term health outcomes across age groups, categories of DSD conditions, and relative to the matched reference cohort. The proposed project will be carried out by a multidisciplinary team that includes experts in DSD research and care, EMR-based data collection, epidemiology, and evaluation of health services.